Thursday, September 30, 2010

The unbelievably heavy rain that clobbered the Carolinas coast is proof once again that it doesn't take a Category 5 hurricane to create big weather problems.

Dying tropical storms, if given some help, can trigger deadly floods, tornadoes, and lots of other trouble.

In some ways, the situation Wednesday and early today on the coast looks similar to 1999, when Hurricane Floyd pushed ashore and set off flooding that killed 51 people. The similarities -- a tropical weather system was involved, and it moved into a stationary front.

Floyd was much, much more powerful than the wimpy Tropical Storm Nicole which died near Florida late Wednesday. But the energy from Nicole was absorbed by a pretty potent non-tropical storm system that formed off the South Carolina coast.

Meanwhile, a stationary front was along the Carolinas coast, separating humid air on the east from cooler air to the west. As low pressure neared the front, it set off very heavy rain.

The National Weather Service in Wilmington says rainfall totals will be in the vicinity of 21 to 23 inches (over a four-day period) when all is said and done.

You know how bad it was? It was so bad that CBS sent meteorologist Dave Price to Wilmington. And the Baron of Bad Weather, Jim Cantore of the Weather Channel, is on the coast.

Meteorologists told you the cut-off between heavy rain and lighter precipitation would be close to the Charlotte area, and they were right. Albemarle got more than 4 inches of rain. Charlotte, about 35 miles to the west, got about 2/3 of an inch. You could draw a line from Greensboro, down across Lexington, Albemarle, eastern Anson County, and then down to Florence ... and everything east of there got walloped by the storm.

Now what?

A taste of autumn, that's what! There's a weak low pressure system over Georgia that will push across our area during the day. The sun might come out at times this afternoon, but that weak low might trigger a few showers or thundershowers.

Clearing will follow tonight, and it'll be nice for a few days, with highs in the 70s and lows in the 50s.

The computers can't agree on Sunday and Monday, with some signs that another coastal storm system could bring rain to the Charlotte area. But after that, it'll turn even more fall-like, with sunshine and highs only around 70 degrees by next Tuesday and Wednesday.

Wednesday, September 29, 2010

At 10:30 this morning, the tropical weather system south of Florida was expected to become Tropical Storm Nicole, cross southern Florida and head for the Carolinas.

Not so fast!

Yes, the tropical depression is now Tropical Storm Nicole, with top sustained winds of 40 mph. But forget about the storm crossing Florida and heading for the Carolinas.

This system has been poorly organized and, frankly, a bit weird from the start. Nicole's strongest winds are about 150 miles east and southeast of the center. And now there are two changes in the forecast:

1. Nicole is expected to pass east of Florida, cross the northwest Bahamas, and move into open waters.

2. It is forecast to dissipate within 36 hours. It will die at sea, maybe 150 or 200 miles east of Jacksonville, without ever reaching the Carolinas.

Does that mean none of the rain is coming to the Charlotte area and the rest of the Carolinas? No, not at all.

Nicole will dissipate because it will be gobbled up by a low pressure system forecast to develop later today off the South Carolina coast. If I may borrow a reference from the distant past, it's like the old Pac-Man game, where one of the little critters gobbles up another.

Once the low pressure system forms off the S.C. coast, it will spread rain inland.

However, this probably means we won't have to worry about flooding rains in Charlotte. Expect an inch or so, from later today until Thursday morning. It'll be great for the lawns.

But how close will the storm's impact come to the Charlotte area? And how much of the Charlotte area?

The bigger question: Will Nicole be drought relief for Charlotte, or a troublemaker?

That all depends on the storm's track, and meteorologists are having a tough time with this system. On Wednesday morning, the disorganized center of the system was about 150 miles south of Key West. Steering winds will carry the storm northward, probably along or near the east coast of Florida.

So far, the depression's strongest winds have been on its eastern side, which means Florida could escape the worst of it (although "worst" might not be the right word, because Nicole won't be a strong tropical storm).

Then, as the storm moves toward anticipated landfall in the Carolinas, it is forecast to lose its tropical characteristics.

When that happens, the area of rainfall widens to all sides of the storm.

The computer models can't agree on how far inland the heavy rain will spread, but it could be very close to the Charlotte area.

Worst-case scenario ... Nicole (or whatever it is, at that point) makes landfall somewhere around Myrtle Beach on a north-northwest track. That would bring 2 to 4 inches of rain to Charlotte, especially along and east of I-77. The farther east you go, the heavier the rain. Places like Richmond and Scotland counties could get 5 inches.

The most likely scenario ... Nicole makes landfall around Wilmington, moving north. Rain moves into Charlotte, but about 1 to 1.5 inches falls. West of I-77, totals are even less. For example, Shelby might get only 1/4 to 1/2 of an inch. That much rainfall for Charlotte would be good.

We'd all get our lawns aerated and make a run on the garden stores for seed and fertilizer.

The rain that moved through the Charlotte area before daybreak was not connected directly with the tropical system. But the precipitation totals give a hint as to what we can expect later. About 1/5 of an inch fell at the airport. A gauge in Matthews measured about 1/3 of an inch. And nearly 1/2 of an inch fell in Monroe.

The farther east you go ...

So here's what to expect: We'll get a break from the rain for a good bit of the day. It might shower once or twice, but that activity will be scattered. Later this afternoon, precipitation from the tropical system will move up the coast and then inland.

Steady rain will begin falling this evening and continue overnight. By later this afternoon, we should have a better idea on what to expect in rainfall totals.

The rain should end Thursday morning, and partial sunshine could return by afternoon.

Look for clear and cooler weather the rest of the week, after a high around 80 Thursday. By Sunday, daytime highs will be near 70.

Tuesday, September 28, 2010

The Carolinas coast is in for a major rainstorm Wednesday and early Thursday, and some of the computers are "telling" meteorologists that heavy rain could spread far inland -- perhaps as far as Charlotte, or at least the eastern suburbs and counties on the east side of the Queen City.

This is a very complex situation, and if you put five meteorologists in the same room, you might get five different forecasts.

The basics:

1. The cold front that pushed through our region Monday has more or less stalled along the coast.

2. A low pressure system is predicted to form along that front Wednesday and move up the coast.

3. A tropical depression that formed today southwest of Cubs is forecast to move northward, perhaps merging with the low off the Carolinas coast.

That means a lot of rain for the coastal areas, where flood watches have been posted.

But over the past 12 hours, the computer-generated forecasts -- called models -- are pushing the heavy rain farther and farther inland. Some of the models predict the combined low pressure system (the regular low and the tropical low) will actually move northward on an inland route, crossing the coastal plain.

What does that mean for the Charlotte area?

For starters, it means you can kiss the earlier forecast of partly cloudy and cool weather for Wednesday and Thursday good-bye! Instead, look for rain to spread from the coast toward Charlotte during the day Wednesday.

By Wednesday night, heavier rain could be falling in the area.

Some computer models predict the heaviest rain (2 to 3 inches) will stay east of the Chesterfield-Anson-Montgomery county line. Other models bring the heavy rain into the Union County-Matthews-Mint Hill-Cabarrus County area. And forecasters are wondering if the models will push the low pressure system even farther inland -- which means heavier rain will reach Charlotte.

One thing's for sure ... the cut-off between rain and no rain will be very sharp. Wherever that cut-off is, you'll be able to drive 15 or 20 miles between dry conditions and rain.

Check back on Wednesday morning for a better idea of what might happen.

Monday, September 27, 2010

Today's Carolinas' weather is featuring a situation seen almost nowhere else in the country.

It's called a cold air wedge (or cold air damming), and we'll talk about it a lot in the coming months, as it's usually seen in our area from late September into April or May.

It's the reason why we sometimes have two or even three different seasons' weather at one time in the Carolinas, depending on where you are.

Today, it's summer at the coast and fall inland, and the dividing line between the seasons could produce some stormy weather later this afternoon as it moves closer to Charlotte.

Cold air damming, or a cold air wedge, is created when cooler air is trapped against the mountains. Typically, the clockwise flow from high pressure over the Northeast sends cooler air into the Carolinas. Cold air is more dense than warm air, and it sinks. The cold air piles up against the mountains and becomes trapped across the foothills, Piedmont and even the sandhills.

When low pressure systems move northward -- sometimes along the coast, sometimes across the Piedmont, and sometimes (like today) across eastern Georgia and eastern Tennessee -- they have a counter-clockwise air flow that tends to drag warmer air from the southeast inland. That often creates a warm front.

Places to the east (coastal side) of the front have temperatures much, much warmer than inland.

At 10 a.m. today, it was 81 degrees in Beaufort and 59 in Asheville. Charlotte's 66-degree reading was 7 degrees cooler than at Myrtle Beach.

I've seen episodes when it was 80 degrees in Columbia and Fayetteville and in the 50s in Charlotte. Sometimes you can drive down I-77 or east on U.S. 74 and encounter a change of 20 degrees' temperature in 10 miles.

Normally, the warm fronts never make it all the way inland past Charlotte. Eventually, the trapped cool air (which is damp and creates clouds and precipitation) is washed out to sea by a stronger cold front.

Today, as the warm front moves slowly inland, meteorologists say it could trigger heavy thunderstorms. The Storm Prediction Center in Norman, Okla., has put south-central North Carolina and much of central and eastern South Carolina in the "risk" area for severe thunderstorms and possibly even a weak tornado later today.

The warm front is a severe weather-producer, in part, because it creates a condition in which winds are spinning from different directions in the atmosphere.

Sunday, September 26, 2010

Well, we've done it ... gone from talking about a drought one day, to worrying about flooding the next.

The National Weather Service has issued a flood watch until Monday evening for nearly all the Charlotte region. Technically, Lancaster and Chesterfield counties of South Carolina are not included, but they could be.

Forecasters say 4 to 6 inches of rain could fall by early Tuesday morning in our area, with the heaviest precipitation expected overnight. Despite the lack of rain for the past month, 4 to 6 inches of rain in a 48-hour period means possible trouble. Hence, the flood watch, despite our dry conditions in recent weeks.

There also is a chance for severe weather tonight, in a corridor from Monroe westward to near Spartanburg -- including Charlotte, Rock Hill and possibly Gastonia. But we'll worry about that later. For now, let's talk about the rain.

Going to the Panthers' game this afternoon. Bring a poncho. Rain moved into the Charlotte area about 11 a.m., and Doug Outlaw, of the National Weather Service's office in Greenville-Spartanburg, said all indications are the showers and thundershowers will increase in coverage this afternoon.

My guess is the highest probability of flooding will be from about midnight until noon Monday, especially in the overnight hours.

The morning commute Monday could be absolutely lovely.

One more thing ... temperatures will start falling this afternoon. The rain is cooling the atmosphere, so our mid 70s of this morning will turn into upper 60s and low 70s this afternoon.

Saturday, September 25, 2010

After weeks of hot, dry weather, it seems almost impossible to be talking about possible flooding concerns, but that's the situation this weekend in the western Carolinas.

Our stagnant weather pattern is not just coming to an end ... it's coming to a crashing halt.

Get ready for a very rainy Sunday, with much cooler weather.

Today will be the end of the summerlike conditions, with partly sunny skies and temperatures approaching 90 degrees this afternoon. It could be our 87th day of 90 degrees or warmer this year -- one short of tying the all-time record, set in 1954.

But the makings of a new pattern are approaching. A cold front is over eastern Tennessee on Saturday morning, and it is predicted to move into the Carolinas later tonight and stall for 24 to 36 hours.

At the same time, low pressure is forming over the Midwest and expected to move into Mississippi before drifting east or northeast on Sunday and Monday.

We could get a thunderstorm this afternoon or evening as the cold front approaches, but more widespread showers and storms are likely tonight, as the low pressure system sinks into the South.

On Sunday, temperatures will hold in the upper 60s and lower 70s. Meanwhile, the low pressure system will spread rain into our area -- not a here-and-there scattered shower situation, but more of a steadier rain. Best guess is that the rain will begin late Sunday morning. By later Sunday afternoon and Sunday evening, the rain could get heavy.

It could be a miserable day at Bank of America Stadium, for the Panthers-Bengals game ... from a weather standpoint. It could be miserable from a football standpoint, too, but that's another issue.

Justin Lane, of the National Weather Service office in Greer, S.C., says 3 to 5 inches of rain is likely in the higher elevations of the foothills and in the Blue Ridge mountains, with 2 to 4 inches in the Piedmont.

"Current forecasts suggest that the rain will fall over a long enough period of time that widespread flooding is not likely, especially given the recent dry conditions," Lane said. However, Lane added, localized areas could have flooding problems, but it's too early to tell where that might happen.

Expect the rain to continue into Monday, with a few thunderstorms added in the mix on Monday. The precipitation probably will end Monday night or Tuesday morning.

By that time, all of our lawns should be soaked enough for us to get the aerating and seeding started.

Once the rain is gone, don't look for a return to the 90s. Forecast highs next week are in the vicinity of 80 degrees, which is still a degree or two above average for this time of year.

Friday, September 24, 2010

Sure, it's only Sept. 24, and we've had 90-degree days well into October in the past, but it sure looks like the 90-degree-plus readings today and possible Saturday will be the end for this year. A dramatic change in the weather pattern is coming.

This doesn't mean warm weather is going away. In fact, you'd better prepare for plenty of above-average temperatures, because all signs are pointing to a mild winter.

But the 90's? They could be history, for this year.

It'll leave us just short of the all-time record of 88 days with 90 degrees or more, set in 1954. Today will be the 86th day this year with 90 or higher in Charlotte, putting 2010 in second place all-time. We might hit 90 again Saturday, for 87 days. Then the change comes.

An upper-atmospheric low pressure system will set up over the eastern United States this weekend, replacing the high pressure heat pump which has parked itself over the Southeast for weeks. That means high temperatures will be in the 70's and 80's for at least the next two weeks. By that time, we'll be well into October, and the latest 90-degree day on record in Charlotte is Oct. 13 (set in that miserably hot summer of 1954 ... we'll need to take a look at that summer one day in this blog).

Another change is coming this weekend -- rain.

We haven't had a major rainfall in Charlotte since the middle of August, but a stalled cold front and a low pressure system will be in the area from late Saturday into Tuesday. Showers and possibly thunderstorms are likely throughout that period.

In fact, Sunday could bring a steady rain, with temperatures only in the lower 70's in the afternoon. Sounds like a fabulous day at Bank of America Stadium, watching the Panthers and Bengals.

The rain is badly needed, and there are signs of additional rainy systems arriving in the area during the next two weeks.

Hurricane Update: Tropical Storm Matthew is moving westward at a pretty good clip at midday Friday, and the betting now is that it never will affect the United States. It is expected to move into Central America, perhaps delivering catastrophic heavy rains in Nicaragua and Honduras. But the system is forecast to dissipate in those countries.

Earlier, computer models indicated Matthew might curve back out to sea, slide northward, and take a run at Florida.

But the Southeast is far from off the hook. Low pressure remains in the Caribbean, and many meteorologist say another system probably will develop there in the next few days. And with the Southeastern U.S. high pressure system having moved offshore, there will be an opening for any hurricane in the Caribbean to push northward toward the Gulf coast of Florida and Alabama.

Thursday, September 23, 2010

As expected, that low pressure system off the Central American coast has developed into a tropical depression, and nearly every meteorologist is expecting the system to be Tropical Storm or Hurricane Matthew by morning.

We now have some computer models to look at, and they take the hurricane into Belize and over the eastern edge of the Yucatan peninsula of Mexico -- and then back into open water south of Florida, heading toward Florida.

This storm is developing in a hurry, and it appears as if the mainland United States will have something to worry about in several days. In the meantime, Matthew could spread devastating heavy rains across Central America this weekend.

Meteorologists agree the weather pattern that has been locked over the Southeast since early to mid August is about to change.

That change will bring cooler weather and a good chance of rain to our area, starting later Saturday or Sunday. We need the rain desperately, and a lot of people are sick of the hot weather and looking for something cooler.

But will the change really be good for us?

Let's take a look at the pattern ...

Strong high pressure has been locked over the Southeast, but the computer models are predicting a changed situation -- high pressure over Texas, and another high over the Atlantic. In between, over the Southeast, will be a weakness in the atmosphere (a trough).

The problem is a weather system currently known as Invest 95L. That's the name given by the National Hurricane Center to an area of stormy weather it is investigating. On Thursday morning, that area was north of Colombia and drifting westward. Invest 95L probably will become a tropical depression later today, and most computer models predict it'll be a hurricane within a few days.

Then what?

It could plow into Belize or Mexico and dissipate -- or weaken so much that it never recovers. But some computer predictions show the storm being dragged northward, by that weakness in the atmosphere over the Southeast. Florida would be at risk, and if such a hurricane made landfall over the Florida Panhandle, its remnants could cause trouble in the western Carolinas.

I saw a report Wednesday from the Weather Channel, in which its meteorologists predict this changed pattern will put the Southeast at risk for the next couple weeks.

Something to remember ... tropical systems that make landfall around Pensacola often bring tornadoes and flooding thunderstorms to the western Carolinas as they move northward.

All of that is a lot of conjecture, and Invest 95L is still just a mass of showers and thunderstorms. But keep that in the back of your mind.

WEATHER TERM OF THE DAY ... Invest.

The National Hurricane Center uses that term for a system it is watching, for data-collecting reasons. The NHC says an "Invest" system isn't necessarily expected to become a tropical depression, tropical storm, or hurricane -- just a system it wants to study. But many "Invest" systems become organized storms. Systems are numbered in order, and the letter signifies the area it is in. The letter "L" is used for systems in the Atlantic Ocean and Caribbean Sea. The letter "E" is used for systems in the eastern Pacific, off the coast of Mexico.

Wednesday, September 22, 2010

I discovered last year, on the 20th anniversary of Hurricane Hugo's pounding of the Carolinas, that some people don't want to hear from those of us who lived through it. "We're tired of hearing about Hugo," I was told several times.

OK. I get it.

But on the 21st anniversary of the day when Hugo came through Charlotte as a Category 1 hurricane -- nearly 200 miles inland -- here's something that should be of interest to both Hugo veterans and those who were born or moved here after Sept. 22, 1989.

I'm betting Hugo was a once-in-a-lifetime experience.

What happened was a complex series of events that isn't likely to happen again for a long, long time.

And what's happened this year in the Atlantic Ocean is an example.

In review ... Hugo was a Cape Verde storm. It developed off the coast of Africa, south of the Cape Verde islands. It retained its strength across the Atlantic and slammed into South Carolina without recurving (curving to the northwest and north). A low pressure system over the Gulf of Mexico and high pressure over New England created a sort of alleyway for Hugo to move -- at a high rate of speed -- inland across South Carolina and Charlotte.

This year has seen a series of powerful hurricanes form in the Cape Verde region. Meteorologists say it's been a busy season. Most people in the United States probably would scoff at that, since the hurricanes didn't hit the mainland.

That's because the storms curved northward. For most of the last two months, there have been two high pressure systems -- one over the central Atlantic, the other over the U.S. Southeast. Between them was a "weakness" area of low pressure.

Each of those Cape Verde hurricanes moved westward across the Atlantic but curved north when they reached that "weakness" area.

"What you're seeing this year is typical for Cape Verde storms," said Scott Krentz, a National Weather Service meteorologist in the Greer, S.C., office. He and other meteorologists say most of those hurricanes curve before hitting the U.S. They become what those of us who follow weather call "fish storms."

Occasionally, the Cape Verde hurricanes get close to the U.S. coast before curving -- a la Hurricane Earl. But having one of those powerful storms slam directly into the Carolinas coast at a 90-degree angle (or close to it) and retain its strength inland is a real rarity.

And my brother Michael, a Texas-based weather weenie who will be mentioned frequently by me, points out that a condition called a negative North Atlantic Oscillation has created a deep dip in the atmosphere over the Atlantic. That also curves storms northward.

Something to watch: Keep an eye on a system that the National Hurricane Center is watching over the southern Caribbean. On Wednesday morning, its center was a bit north of Aruba. Some computer models predict that system could become a strong hurricane next week in the Gulf of Mexico. Other models show the storm hitting Mexico or Central America.

As we learned from Hurricane Ike two years ago, Gulf hurricanes can mean big trouble here in the Carolinas, even if the wind and rain never get within 600 miles of us. A disruption in petroleum operations in the Gulf can translate into $5-a-gallon gas for us. We don't like Gulf hurricanes.

Tuesday, September 21, 2010

At the beginning of the movie "Twister," there's a scene in which a young Jo Harding (played by Alexa Vega) watches as a tornado sucks her father from a shelter on their Midwest farm. That event fueled her fixation with tornadoes.

For me, it was a night at the Eastlake Drive-In, a few miles from my home in northeastern Ohio. It happened decades ago -- OK, many decades ago -- when my dad took me and two of my brothers to see a movie. A severe storm swept across the area, nearly overturning our Ford station wagon.

What normally was a 10-minute ride home took us hours, as we tried to find a street that wasn't blocked by downed trees. After that, I was a weather geek.

This if the first post of "Weather Guy," my new blog, and I want this to be a place for discussion between myself and other weather geeks -- and there are many of you out there. I also think this blog will be a chance to report weather news that otherwise wouldn't be a part of the Observer's main news coverage.

I'll share some weather trivia and tell you about some of the interesting websites I've discovered. And I'm sure you'll show me a few that I haven't found.

Let's set one thing straight. I'm not a meteorologist. Meteorology is physics and math. I don't know if my high school physics teacher, Mr. Murawa, is still alive, but he would cringe at the thought of my writing about something involving physics. I got a "D" for the year, and that was generous.

But over the last 10 or 15 years, I've asked meteorologists hundreds of questions, I've read dozens of books, I've attended seminars and workshops, and I've learned a lot.

Here are five of my core meteorological beliefs:

1. The greatest influence on me was Dick Goddard, a legendary Cleveland TV meteorologist since 1961. He's 79 and still on the air every day. If he can't get you interested in weather, nobody can.

2. I was here in Charlotte for Hurricane Hugo, but my most memorable storm was Jan. 26, 1978 -- an incredible blizzard that swept across the Great Lakes with winds and barometric readings low enough for a hurricane. I'll write about this storm in the future. Hugo was memorable, too, though. And Wednesday is the 21st anniversary. (Personal note: That blizzard was enough for me ... I moved to Charlotte five months later.)

3. Charlotte has an amazing number of truly talented meteorologists -- a lot more than you'd expect for a city this size. Some of them -- Eric Thomas, Brad Panovich, John Wendel, Mike Dross, Jeff Crum -- are good people who have been very helpful to me.

4. The scariest weather event for me isn't tornadoes or hurricanes. It's giant waves, and I even have nightmares about them. Other than Kate Gosselin, it's the scariest thing I see on my TV set. I'll write about waves, too.

5. I hate snow. I spent the first 28 years of my life in the snow belt of northeastern Ohio. That was enough snow for three lifetimes.

About this blog

Steve Lyttle says growing up in northeastern Ohio, with its foot-deep snows and summertime severe thunderstorms, fueled his interest in meteorology. He has written about weather for 10 years at The Observer. Join the discussion about weather trends and weird weather events -- whether local or around the world.